Electrical Engineering V3 - Developers

"Hey this routing job shouldn't be too bad" [IMG]http://i.imgur.com/zUS0XGT.png[/IMG] "... I've made a horrible mistake" According to Eagle I'm at a total of 150 vias.

What are you doing? Look cool though, there is not a lot you can do with so many pins.

Trying to hook up a whole lot of peripherals to an XMOS chip (weird little bugger). For some reason the upper 8 bits of the 16-bit input I used for the SDRAM aren't bonded out in order, which is responsible for most of the mess. I don't have a lot of experience with these kinds semi-high-speed designs though, so I feel like I'm either gonna have EMI issues or problems with dirty power.

Hey guys, Im a long time lurker and first year student in computer engineering technology, and today I just became an IEEE member and joined my colleges local branch. Whats up?

[QUOTE=pentium;50046700]Is there any form of modern version of the [url=https://www.tindie.com/products/reinnovation/dataduino-the-arduino-based-data-logger/]DataDuino[/url]? I have a project here that requires me to log every ten seconds or so an NMEA formatted sentence to an SD/CF card via RS-232.[/QUOTE] [url]https://www.adafruit.com/products/2795[/url] could do it. Plus it is really cool on the other feathers they have as well.

[QUOTE=Zombie_2371;50048397]Hey guys, Im a long time lurker and first year student in computer engineering technology, and today I just became an IEEE member and joined my colleges local branch. Whats up?[/QUOTE] does your ieee do anything cool? we do ieeextreme and they have dudes come and talk every so often but nothing else really. also southeast con but i didn't go

[QUOTE=elitehakor;50049304]does your ieee do anything cool? we do ieeextreme and they have dudes come and talk every so often but nothing else really. also southeast con but i didn't go[/QUOTE] We have workshops and stuff all the time, I dont know much since I literally just joined

I know this might be a longshot, but does anyone know of a heavy-duty replacement for Omron D2FC-F-7N switches? They seem to only last just over two years of use, and they're also used in incredibly many computer mice, ranging from both cheap shitty ones, to ones right below the pricebracket where manufacturers offers extended warranties. So I'm on the lookout for said tougher replacements for both repairing my current mouse, and for future repairs of other mice.

So I haven't yet put together the second LED panel for my plants due to school and work and general laziness, but it gave me time to observe how my plants react to the panel and I have to say it's quite impressive. Growth is not lanky and plants are not stretched. Growth has been very lush and green. So I guess my research into optimal wavelengths has paid off quite nicely. I have so many plants that I don't know what to do with. I actually have been eating strawberries all winter long and I also have some onions that are ready for harvest... Which I started early to place outside. I'm going to build a new panel because even though my plants are very healthy, all but two of red LEDs have burned out and I have some improvement ideas that I want to apply. I'll have to use these [url]http://www.ebay.com/itm/10-pcs-DC-DC-LM2596-Step-Down-Adjustable-Converter-Power-Supply-Module-1-3V-35V-/221778445690?hash=item33a306857a[/url] in the next build so the lower voltage LEDs don't burn out within a month. I've had this LED panel running continuously since early December I believe.

[QUOTE=Van-man;50049800]I know this might be a longshot, but does anyone know of a heavy-duty replacement for Omron D2FC-F-7N switches? They seem to only last just over two years of use, and they're also used in incredibly many computer mice, ranging from both cheap shitty ones, to ones right below the pricebracket where manufacturers offers extended warranties. So I'm on the lookout for said tougher replacements for both repairing my current mouse, and for future repairs of other mice.[/QUOTE] Honywell ZX10 series, such as ZX10C30A01 is a perfect match, only slight difference is the addition on a NC terminal in place of the dummy terminal on the D2FC-F-7N and slightly different pins in the 0.1A range. [QUOTE=Tobba;50047850]Trying to hook up a whole lot of peripherals to an XMOS chip (weird little bugger). For some reason the upper 8 bits of the 16-bit input I used for the SDRAM aren't bonded out in order, which is responsible for most of the mess. I don't have a lot of experience with these kinds semi-high-speed designs though, so I feel like I'm either gonna have EMI issues or problems with dirty power.[/QUOTE] Do your best to fan out the IC first before anything else, then add the decoupling before finally doing the vias, EMI is only really a concern where you have high speed clocks or a serial bus, as long as you keep those away from other traces as much as possible you'll be fine, do try minimize traces under the chip though, once you get all the traces neatly out you'll find you don't need quite as many vias, don't worry about using plenty of vias around the chip.

[QUOTE=Tobba;50047850]Trying to hook up a whole lot of peripherals to an XMOS chip (weird little bugger). For some reason the upper 8 bits of the 16-bit input I used for the SDRAM aren't bonded out in order, which is responsible for most of the mess. I don't have a lot of experience with these kinds semi-high-speed designs though, so I feel like I'm either gonna have EMI issues or problems with dirty power.[/QUOTE] Heh, one of my lecturers started the company that makes those parts :)

I was desperate to convert 12v to 5v, so I cannibalized a cigarette lighter adapter. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/IMG_3358.jpg[/IMG] [IMG]http://i11.photobucket.com/albums/a166/ballsandy/IMG_3359.jpg[/IMG]

[QUOTE=ben1066;50051299]Heh, one of my lecturers started the company that makes those parts :)[/QUOTE] They're really quite weird, like the Propeller but actually economical to use; I don't actually have a clue if it can keep up with the calculations it needs to do though. In [I]theory [/I]it can get 4x the performance of an equivalently priced ARM9 core (in terms of ALU ops/second), but no compiler in existence is going to generate code that can push the chip that far without serious coaxing, and a lot of the threads are used up to control peripherals. Not to mention the documentation is somewhat garbage.

I really want to love the Propeller for the sheer novelty of a multicore uController, but the compiled language Spin as well as the documentation behind said language is just garbage. They show examples and rarely explain how to address/initialize the various modules.

Testing supply from eBay. Slightly ghetto, and not much load, but it works. Very low current, but oh well. [t]https://i.imgur.com/ePDXcod.jpg[/t] [t]https://i.imgur.com/i5Br129.jpg[/t] The mains plug is a 40W 230V desk lamp. [editline]2nd April 2016[/editline] Lamp wasn't enough load, so I put a 200R 5W resistor, in water, in parallel with the lamp. I confirmed there's no short circuit, and the temperatures stay in check. Neat.

Sometimes those things are actually pretty well made. We have one for a few 12v radios up at our club and it's been kicking for three years now, no issues, and still holds 13.8V perfectly.

Is it a proper supply, or the cheapest Chinese piece of shit on eBay, though?

[QUOTE=Chryseus;50051102]Do your best to fan out the IC first before anything else, then add the decoupling before finally doing the vias, EMI is only really a concern where you have high speed clocks or a serial bus, as long as you keep those away from other traces as much as possible you'll be fine, do try minimize traces under the chip though, once you get all the traces neatly out you'll find you don't need quite as many vias, don't worry about using plenty of vias around the chip.[/QUOTE] Thanks for the advice. Is there any reason to avoid traces/vias under the chip other than that it makes it really easy to route yourself into a corner? Worst I could imagine is the chip not lying perfectly evenly on the board when reflowing.

Finished load testing all the cells in a rebuilt battery, one at a time. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/discharge.png[/IMG] Cells 1, 2 and 10 were falling below threshold before they should of and need to be replaced.

Anyone found a reliable source for raw LCD panels, just the panel and the controller (looking for an ILI9431 display, can find lots of docs). I've found various with the same physical dimensions (2.8" display, same active and physical area etc), but they often seem to have incompatible interfaces when looking on AliExpress or such. I've actually emailed a couple LCD manufacturers in China to see if I can get anywhere directly, but I'm hesitant, though one of them appears to keep stock, so maybe it'll just be a heafty shipping cost. I kinda plan to make a few units depending upon how much motivation I have, so I would like to be able to find a source that won't change tomorrow, does that exist without paying huge $$$ for the displays?

TIL it's a very bad idea to assume a random wall wart from my drawer outputs DC and that I have a 230VAC -> 12VAC wall wart in said drawer :v:

[QUOTE=ben1066;50071035]Anyone found a reliable source for raw LCD panels, just the panel and the controller (looking for an ILI9431 display, can find lots of docs). I've found various with the same physical dimensions (2.8" display, same active and physical area etc), but they often seem to have incompatible interfaces when looking on AliExpress or such. I've actually emailed a couple LCD manufacturers in China to see if I can get anywhere directly, but I'm hesitant, though one of them appears to keep stock, so maybe it'll just be a heafty shipping cost. I kinda plan to make a few units depending upon how much motivation I have, so I would like to be able to find a source that won't change tomorrow, does that exist without paying huge $$$ for the displays?[/QUOTE] [URL="http://www.buydisplay.com/"]BuyDisplay[/URL] is run by EastRising Technology, which produces different displays. It's their factory store. So you might want to look around there. There's also LCDChina, but the website is kinda, terrible.

[QUOTE=Goz3rr;50073408]TIL it's a very bad idea to assume a random wall wart from my drawer outputs DC and that I have a 230VAC -> 12VAC wall wart in said drawer :v:[/QUOTE] I found out one of my wallwarts makes a terrible noise if not plugged into a load. It also very easily slips out of the device its plugged into which is concerning.

So I'm working on an Atari 800, and I need to replace a connector. It's a strange piece and I'm wondering if any of you would happen to know the name of it or where I can buy a replacement. I found one place online but the guy has a minimum order of 50$ with paypal(which is the only way I would want to pay some random guy) and lists this as only a 2 dollar part, he also only has an Atari specific product number for it so that was no help in finding the part outside his inventory. The pins come up through the board (hence the slot in the bottom) into the connector housing and are pressed on by small springy contacts inside. I tried to photograph this as best I could to give you all an idea of what's going on. I know this isn't a connector unique to Atari because I actually spotted the exact same connector in a fire alarm I was working on at work today, although it had only 10 pins or so compared to this one at 22. It's off an Atari 800 power-board. If any of you have any idea I would really appreciate it! [thumb]http://i.imgur.com/gV2bBhQ.jpg[/thumb] [thumb]http://i.imgur.com/z14I9OC.jpg[/thumb] [thumb]http://i.imgur.com/HA7DS1L.jpg[/thumb] [thumb]http://i.imgur.com/GzctneN.jpg[/thumb] [thumb]http://i.imgur.com/8geq1rL.jpg[/thumb]

Try measuring the pitch (Distance between each pin), if its 0.1"/2.54mm you can simply use a normal male header trimmed to 22 pins. I'd also try emailing the guy with the specific part, see if you can negotiate with him to drop the minimum $50 order. Its irritating when sellers do that for hard-to-find items, but you can atleast try negotiating.

It looks basically like a regular pin socket flipped upside down. You can probably substitute it using a new pin header block and some hot glue. Failing that, if you have access to one of those 10 pin connectors you mentioned steal that, cut off the damaged half and graft in the new block.

That feeling when you are a little over a day away from piles of free test equipment. It's like Christmas. AAAAAAAAAAAAAAAAAAAAAAAAAA.

[img]http://puu.sh/oaYZw/e709b6c617.jpg[/img] It's a tough life for robots in the sex industry.... You see them cozyed up in the corners of industrial units smoking sometimes.

[quote]When you realize after the boards are fabbed that the pinout was wrong.[/quote] [img]http://www.rbarrios.com/projects/HP70004/10.jpg[/img]

[QUOTE=pentium;50096343][img]http://www.rbarrios.com/projects/HP70004/10.jpg[/img][/QUOTE] Not as bad as using the wrong footprint altogether.